1. Field of the Invention
The present invention relates to a semiautomatic-automatic strapping machine which can be used as an automatic strapping machine by fitting an arch guide and can be converted to a semiautomatic strapping machine by detaching the arch guide.
2. Description of the Prior Arts
It has been known to provide a band feeding and tightening system in a strapping machine. A semiautomatic strapping machine has been usually required for strapping articles having different sizes whereas an automatic strapping machine has been usually required for strapping articles having the same or similar sizes.
The detail of the semiautomatic strapping machine is wellknown. In the semiautomatic strapping machine, an article is wound by a plastic band fed from a band feeder and the plastic band is tightened and melt-bonded at both ends to provide a packaging. In the automatic strapping machine, a plastic band is automatically fed to an arch guide in a looped condition and it is tightened and melt-bonded.
As one of the conventional band feeding and tightening apparatus, it has been proposed to use an apparatus disclosed in Japanese Utility Model Publication No. 23280/1965, in which a return roller and a feed roller rotated at a high speed in the reverse direction to each other are disposed in spaced relation and rocker rollers are provided to selectively contact with the rollers respectively so as to feed the band at a high speed or to tighten the band.
Sometimes, it is preferable to use a semiautomatic strapping machine whereas sometimes it is preferable to use an automatic strapping machine.
The structure of the semiautomatic strapping machine is quite different from the structure of the automatic strapping machine and the functions of these strapping machines are quite different with each other.
Some users wish to operate the semiautomatic strapping machine as an automatic strapping machine sometimes depending upon sizes and configurations of the articles and other operating conditions, whereas some users wish to operate the automatic strapping machine as a semiautomatic strapping machine.
However, the design of the semiautomatic strapping machine is quite different from the design of the automatic strapping machine and accordingly, it has been difficult to convert them with each other.